I hate to say this cause I have no ill feeling toward Kira or Shinn, but if anyone is to blame for Stellar taking out a whole city it should be Neo. He is the one who put her in there, of course he was ordered to but he broke his promise. You could even go further and blame what Stellar did on Shinn, had he never brought her back she would have never destroyed the city. However, I agree with PSJ that if it wasn't Stellar behind the Destroy, it would have been someone else. The reason why Stellar went beserk again was because Neo put it in her head that "bad people are trying to kill us" or something like that. So, since Freedom was attacking her, Freedom became IT (a game of IT with him being the bad guy in her eyes). I understand some people's deep hated root for Kira (although I do not feel it myself), and I respect the opinions and statements of those who believe Kira is to blame. Yet, I have stated the reasoning why I believe that train of thought is inaccurate, in my opinion.